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Desorption/Diffusion of Benzene After Simulated Ground Water Remediation

Description: A study was undertaken to examine the desorption/ iffusion of benzene after simulated ground water remediation in aquifer material of differing carbon content using column experiments and comparing the results to batch experiments and adsorption empirical relationships. It was hypothesized that the organic carbon of the aquifer material will affect desorption/diffusion. Results from the column experiment indicated no significant difference in the increase benzene concentrations after remediation between aquifer materials of differing carbon content, however, a significant increase in benzene concentration was observed for all aquifer material. Fair agreement of retardation factors was observed between empirical relationships and batch and column experiments. However, the desorption phase of the batch experiment showed hysteresis and seemed to differ from the column experiment.
Date: December 1989
Creator: Bennett, Kathryn C. (Kathryn Condreay)
Partner: UNT Libraries

ITP Filtrate Benzene Removal Alternatives

Description: Existing ITP filtrate hold tanks may provide sufficient capacity and residence time to strip dissolved benzene from the incoming filtrate using nitrogen sparging in the bottom of the old tanks. This is based on equilibrium supported by late Wash test data using aged washed slurry. Theoretical considerations indicate that benzene stripping will be more difficult from the ITP unwashed high salt filtrates due to reduced mass transfer. Therefore experimental sparging data is needed to quantify the theoretical effects.Foaming limits which dictate allowable sparging rate will also have to be established. Sparging in the hold tanks will require installation of sintered metal spargers, and possibly stirrers and foam monitoring/disengagement equipment. The most critical sparging needs are at the start of the precipitation/concentration cycle, when the filtrate flux rate is the highest,and at the end of wash cycle where Henry`s equilibrium constant falls off,requiring more gas to sparge the dissolved benzene. With adequate recycle (for proper distribution) or sparging in the old tanks, the 30 inch column could be used for the complete ITP process. A courser packing would reduce back pressure while enabling benzene stripping. The Late Wash Tests indicate adequate benzene stripping even at reduced gas flow. This will require experimental verification under ITP conditions. Using the 30 in. column vs 18 in. during the wash cycle will enhance stripping without need for additional sparging provided the minimum flow requirements are met.
Date: May 21, 1993
Creator: Dworjanyn, L.O.
Partner: UNT Libraries Government Documents Department

Study of Substituted Benzenesulfonate-Containing Layered Double Hydroxides and Investigation of the Hexamethylenetetramine Route of LDH Synthesis

Description: Benzenesulfonates, para-substituted with amine, chloride and methyl groups were successfully incorporated into layered double hydroxides of two different compositions, 2:1 Mg-Al LDH and 2:1 Zn-Al LDH. These parent materials were also doped with small amounts of nickel and the differences in the two systems were studied. The hexamethylenetetramine route of layered double hydroxide synthesis was investigated to verify if the mechanism is indeed homogeneous. This included attempting preparation of 2:1 Mg-Al LDH, 2:1 Zn-Al LDH and 2:1 Zn-Cr LDH with two different concentrations of hexamethylenetetramine. The analytical data of the products suggest that the homogeneous precipitation may not be the true mechanism of reaction involved in LDH synthesis by this method.
Date: May 2007
Creator: Ambadapadi, Sriram
Partner: UNT Libraries

Reactions of the CN Radical with Benzene and Toluene: Product Detection and Low-Temperature Kinetics

Description: Low temperature rate coefficients are measured for the CN + benzene and CN + toluene reactions using the pulsed Laval nozzle expansion technique coupled with laser-induced fluorescence detection. The CN + benzene reaction rate coefficient at 105, 165 and 295 K is found to be relatively constant over this temperature range, 3.9 - 4.9 x 10-10 cm3 molecule-1 s-1. These rapid kinetics, along with the observed negligible temperature dependence, are consistent with a barrierless reaction entrance channel and reaction efficiencies approaching unity. The CN + toluene reaction is measured to have a slower rate coefficient of 1.3 x 10-10 cm3 molecule-1 s-1 at 105 K. At room temperature, non-exponential decay profiles are observed for this reaction that may suggest significant back-dissociation of intermediate complexes. In separate experiments, the products of these reactions are probed at room temperature using synchrotron VUV photoionization mass spectrometry. For CN + benzene, cyanobenzene (C6H5CN) is the only product recorded with no detectable evidence for a C6H5 + HCN product channel. In the case of CN + toluene, cyanotoluene (NCC6H4CH3) constitutes the only detected product. It is not possible to differentiate among the ortho, meta and para isomers of cyanotoluene because of their similar ionization energies and the ~;; 40 meV photon energy resolution of the experiment. There is no significant detection of benzyl radicals (C6H5CH2) that would suggest a H-abstraction or a HCN elimination channel is prominent at these conditions. As both reactions are measured to be rapid at 105 K, appearing to have barrierless entrance channels, it follows that they will proceed efficiently at the temperatures of Saturn?s moon Titan (~;;100 K) and are also likely to proceed at the temperature of interstellar clouds (10-20 K).
Date: December 23, 2009
Creator: Trevitt, Adam J.; Goulay, Fabien; Taatjes, Craig A.; Osborn, David L. & Leone, Stephen R.
Partner: UNT Libraries Government Documents Department

JV Task 86 - Identifying the Source of Benzene in Indoor Air Using Different Compound Classes from TO-15 Data

Description: Volatile organic compound (VOC) data that had already been collected using EPA method TO-15 at four different sites under regulatory scrutiny (a school, strip mall, apartment complex, and business/residential neighborhood) were evaluated to determine whether the source of indoor air benzene was outdoor air or vapor intrusion from contaminated soil. Both the use of tracer organics characteristic of different sources and principal component statistical analysis demonstrated that the source of indoor air at virtually all indoor sampling locations was a result of outdoor air, and not contaminated soil in and near the indoor air-sampling locations. These results show that proposed remediation activities to remove benzene-contaminated soil are highly unlikely to reduce indoor air benzene concentrations. A manuscript describing these results is presently being prepared for submission to a peer-reviewed journal.
Date: April 15, 2007
Creator: Hawthorne, Steven B.
Partner: UNT Libraries Government Documents Department


Description: Wet Air Oxidation (WAO) is one of the two technologies being considered for the destruction of Tetraphenylborate (TPB) in Tank 48H. Batch bench-scale autoclave testing with radioactive (actual) Tank 48H waste is among the tests required in the WAO Technology Maturation Plan. The goal of the autoclave testing is to validate that the simulant being used for extensive WAO vendor testing adequately represents the Tank 48H waste. The test objective was to demonstrate comparable test results when running simulated waste and real waste under similar test conditions. Specifically: (1) Confirm the TPB destruction efficiency and rate (same reaction times) obtained from comparable simulant tests, (2) Determine the destruction efficiency of other organics including biphenyl, (3) Identify and quantify the reaction byproducts, and (4) Determine off-gas composition. Batch bench-scale stirred autoclave tests were conducted with simulated and actual Tank 48H wastes at SRNL. Experimental conditions were chosen based on continuous-flow pilot-scale simulant testing performed at Siemens Water Technologies Corporation (SWT) in Rothschild, Wisconsin. The following items were demonstrated as a result of this testing. (1) Tetraphenylborate was destroyed to below detection limits during the 1-hour reaction time at 280 C. Destruction efficiency of TPB was > 99.997%. (2) Other organics (TPB associated compounds), except biphenyl, were destroyed to below their respective detection limits. Biphenyl was partially destroyed in the process, mainly due to its propensity to reside in the vapor phase during the WAO reaction. Biphenyl is expected to be removed in the gas phase during the actual process, which is a continuous-flow system. (3) Reaction byproducts, remnants of MST, and the PUREX sludge, were characterized in this work. Radioactive species, such as Pu, Sr-90 and Cs-137 were quantified in the filtrate and slurry samples. Notably, Cs-137, boron and potassium were shown as soluble as a result of the WAO reaction. ...
Date: March 31, 2009
Creator: Adu-Wusu, K & Paul Burket, P
Partner: UNT Libraries Government Documents Department

ORGANIC COOLANT RECLAMATION. Quarterly Progress Report No. 3 for June 15, 1959-September 15, 1959

Description: In the third quarter of research on organic coolant reclamation, reaction conditions which show promise as reclamation prccedures were found in two major areas of investigation. In the study of hydrocracking of polyphenyls, ten catalysts show activity. One of these, a platinum on alumina, gives a very clean reaction with high conversions per pass and high yields in the model systems under study. The redistribution reaction in the model case of benzene and p-terphenyl gave reproducible results with high enough conversion to be of interest for reclamation. ( For preceding period see AECU-4268.) (auth)
Date: October 15, 1959
Creator: Wineman, R.J.; Adams, J.S. & Scola, D.A.
Partner: UNT Libraries Government Documents Department


Description: The C/sup 1//sup 1/-C/sup 1//sup 4/ components of a sample of"Ultrasene" were identified as normal- and iso-paraffins; mono-, bi-, and tri-cycloparaffins; alkylbenzenes; indans; indenes; naphthalenes; and acenaphthenes. The aromatic content of this sample was 3.0 vol%. (auth)
Date: April 1, 1961
Creator: Wilhite, R. N.
Partner: UNT Libraries Government Documents Department

First Principals and Classical Molecular Dynamics Simulations of Solvated Benzene

Description: We have performed extensive ab initio and classical MD simulations of benzene in water in order to examine the unique solvation structures that are formed. Qualitative differences between classical and ab initio MD simulations are found and the importance of various technical simulation parameters is examined. Our comparison indicates that non-polarizable classical models are not capable of describing the solute-water interface correctly if local interactions become energetically comparable to water hydrogen bonds. In addition, a comparison is made between a rigid water model and fully flexible water within ab initio MD simulations which shows that both models agree qualitatively for this challenging system.
Date: September 11, 2007
Creator: Allesch, M; Lightstone, F; Schwegler, E & Galli, G
Partner: UNT Libraries Government Documents Department

Characterization Of The Hydrogenation Products Of Bix (phenylethynyl) Benzene (DEB) Getter Using Combined GC/FTIR/MS, FT-Raman, and ATR Spectroscopies (U)

Description: Organic hydrogen getters are utilized to minimize hydrogen accumulation in sealed systems where such build up could produce either a safety problem from pressure build up or corrosion problem due the hydriding of metals contained in the sealed vessel. DEB (1,4 bis (phenyl ethynyl) benzene) is a hydrogen getter that is based on the palladium catalyzed hydrogenation of triple bonds to single bonds in aromatic aryl compound. DEB is a getter mixed with 25% carbon and 1% Pd and pressed into pellets with some porosity. The reaction mechanisms are complex involving solid state reactions with a heterogeneous catalyst leading to the many intermediates.
Date: June 9, 2011
Creator: Smyrl, N. R. & Powell, G. L.
Partner: UNT Libraries Government Documents Department

Changes in the peripheral blood transcriptome associated with occupational benzene exposure identified by cross-comparison on two microarray platforms

Description: Benzene is an established cause of leukemia and a possible cause of lymphoma in humans but the molecular pathways underlying this remain largely undetermined. This study sought to determine if the use of two different microarray platforms could identify robust global gene expression and pathway changes associated with occupational benzene exposure in the peripheral blood mononuclear cell (PBMC) gene expression of a population of shoe-factory workers with well-characterized occupational exposures to benzene. Microarray data was analyzed by a robust t-test using a Quantile Transformation (QT) approach. Differential expression of 2692 genes using the Affymetrix platform and 1828 genes using the Illumina platform was found. While the overall concordance in genes identified as significantly associated with benzene exposure between the two platforms was 26% (475 genes), the most significant genes identified by either array were more likely to be ranked as significant by the other platform (Illumina = 64%, Affymetrix = 58%). Expression ratios were similar among the concordant genes (mean difference in expression ratio = 0.04, standard deviation = 0.17). Four genes (CXCL16, ZNF331, JUN and PF4), which we previously identified by microarray and confirmed by real-time PCR, were identified by both platforms in the current study and were among the top 100 genes. Gene Ontology analysis showed over representation of genes involved in apoptosis among the concordant genes while Ingenuity{reg_sign} Pathway Analysis (IPA) identified pathways related to lipid metabolism. Using a two-platform approach allows for robust changes in the PBMC transcriptome of benzene-exposed individuals to be identified.
Date: March 1, 2009
Creator: McHale, Cliona M.; Zhang, Luoping; Lan, Qing; Li, Guilan; Hubbard, Alan E.; Forrest, Matthew S. et al.
Partner: UNT Libraries Government Documents Department

Exposure to motor vehicle emissions: An intake fraction approach

Description: Motor vehicles are a significant source of population exposure to air pollution. Focusing on California's South Coast Air Basin as a case study, the author combines ambient monitoring station data with hourly time-activity patterns to determine the population intake of motor vehicle emissions during 1996-1999. Three microenvironments are considered wherein the exposure to motor vehicle emissions is higher than in ambient air: in and near vehicles, inside a building that is near a freeway, and inside a residence with an attached garage. Total motor vehicle emissions are taken from the EMFAC model. The 15 million people in the South Coast inhale 0.0048% of primary, nonreactive compounds emitted into the basin by motor vehicles. Intake of motor vehicle emissions is 46% higher than the average ambient concentration times the average breathing rate, because of microenvironments and because of temporal and spatial correlation among breathing rates, concentrations, and population densities. Intake fraction (iF) summarizes the emissions-to-intake relationship as the ratio of population intake to total emissions. iF is a population level exposure metric that incorporates spatial, temporal, and interindividual variability in exposures. iFs can facilitate the calculation of population exposures by distilling complex emissions-transport-receptor relationships. The author demonstrates this point by predicting the population intake of various primary gaseous emissions from motor vehicles, based on the intake fraction for benzene and carbon monoxide.
Date: May 1, 2002
Creator: Marshall, Julian D.
Partner: UNT Libraries Government Documents Department

Energetics and kinetics of anaerobic aromatic and fatty acid degradation. Progress report, March 1992--June 1995

Description: Factors affecting the rate and extent of benzoate degradation by anaerobic syntrophic consortia were studied. Cocultures of a syntrophic benzoate degrader, strain SB, with a hydrogen/formate-using sulfate reducer degraded benzoate to a threshold that depended on the amount of substrate and acetate present. The benzoate threshold was not a function of the inhibition of benzoate degradation capacity by acetate or the toxicity of the undissociated form of acetate. Rather, a critical or minimal Gibb`s free energy value may exist where thermodynamic constraints preclude further benzoate degradation. A sensitive assay to detect low formate concentrations was developed to measure the formate levels when the benzoate threshold was reached. We showed that increased acetate concentrations, even when hydrogen and formate levels are low, affects the extent of benzoate degradation, implicating the importance of interspecies acetate transfer. In addition to benzoate, various saturated and unsaturated fatty acids, 2-methylbutyrate, and methyl esters of fatty acids supported growth in coculture with a hydrogen-using partner. SB is the only syntrophic bacterium known to use both benzoate and fatty acids. Phylogenetic analysis showed that SB clustered with sulfate reducers in the delta subclass of the Proteobacteria. SB grew well in coculture with Desulfoarculus baarsii, a sulfate reducer that uses formate but not hydrogen. This unequivocally shows that SB can grow by interspecies formate transfer.
Date: June 23, 1995
Creator: M.J., McInerney
Partner: UNT Libraries Government Documents Department

Evaluating Defoaming Agents for the Stripping Columns at the In-Tank Precipitation Facility

Description: The In-Tank Precipitation (ITP) process will concentrate the Tank 48 contents to approximately 10 wt. percent tetraphenylborate solids by filtration. The filtrate produced during the process flows to the ITP stripping columns where the soluble benzene is removed from the solution. It has been observed that a large pressure differential occurs across the column packing when the filtrate is processed in the column. One potential explanation for the pressure differential is that the filtrate is foaming in the column. Small scale stripping tests have verified that the salt solution foams. Waste Management requested assistance from SRTC in solving the foaming problem through technical task requests HLE-TTR-93013A/B (Benzene Stripper Performance Evaluation) and HLE-TTR-93044 (Kinetics of Benzene and Dissolution). Various tests were completed to determine an effective defoaming agent for use in the stripping columns. This document discusses the tests and the conclusions.
Date: June 30, 1993
Creator: McGlynn, J.F.
Partner: UNT Libraries Government Documents Department

Tetraphenylborate Solids Stability Tests

Description: Tetraphenylborate solids provide a potentially large source of benzene in the slurries produced in the In-Tank Precipitation process. The stability of the solids is an important consideration in the safety analysis of the process and we desire an understanding of the factors that influence the rate of conversion of the solids to benzene.
Date: December 19, 1997
Creator: Walker, D.D. & Edwards, T.B.
Partner: UNT Libraries Government Documents Department